I know exactly what you're going through lol. it still happens to me - i'll stay a certain skill level for a very long time and wonder if i'll ever improve again, but i keep playing and every time i ALWAYS improve, no matter how much i think i wont lol.
It's more a matter of if you can be patient. people overcomplicate improving at the game. although it's a bit of a meme, it's quite true that the only way to improve is by playing more. if you just keep playing you will always improve at some point. don't overthink improving, once you stop thinking so much about it you will improve faster than you ever did before.